The present invention relates to systems for transmission of electrical power and data signals and in particular to systems which can be used to transmit power and signals between electrical units which must be electrically isolated from each other.
With the increasing use of electrically and electronically controlled appliances, particularly but not exclusively appliances for domestic use, an ever increasing effort must be made to ensure that these appliances are electrically safe.
The consequences of electric shock to a user are rarely higher in the domestic environment than in the bathroom. The designer of appliances to be fitted or used there must pay the highest regard to all practical methods of minimising risks of electric shock to the user, and this is particularly important when the user is required to control the appliance from inside the bathtub or shower.
It is therefore essential that a user be fully protected from a mains or other high voltage electrical power supply employed in operation of a bathroom system such as a whirlpool bath (that is a bath in which jets of air, water, or an air/water mixture are pumped into the bath under the surface of the water); such supply would ordinarily be used in a whirlpool installation to power an air heater and blower which can be controlled by the user. Control circuitry can be arranged to operate at a low, safe, voltage, but danger to the user can still arise from any possibility (through the introduction of water, an electrical fault, or otherwise) of control elements handled by the user becoming live from connection with the high voltage power supply.